Sterilizing compositions comprising phosphors for converting electromagnetic radiation to UVC radiation and methods for using the same

ABSTRACT

There is disclosed a composition for converting electromagnetic energy to ultraviolet C (UVC) radiation or radiation of a shorter wavelength, the composition comprising at least one phosphor capable of converting an initial electromagnetic energy (A) to an electromagnetic energy (B) comprising UVC radiation or radiation of a shorter wavelength, and an organic or inorganic media containing said phosphor. There is also a method of sterilizing an article by exposing it to UVC radiation or radiation of a shorter wavelength for a time sufficient to deactivate or kill at least one microorganism and/or for a time sufficient to inhibit abnormal cell growth within the body, when said composition is in an implantable medical device. A method of coating an article with such compositions is also disclosed.

This application is a divisional of U.S. patent application Ser. No.12/269,900, filed Nov. 13, 2008, now U.S. Pat. No. 8,236,239, whichclaims the benefit of provisional application 60/988,466, filed Nov. 16,2007, both of which are incorporated herein by reference.

The present invention relates to a germicidal composition that can beformed into or used in various consumer, medical, and industrialproducts. The composition comprises organic or inorganic phosphors thatconvert an incident radiation to UVC radiation or electromagneticradiation of shorter wavelengths, such as x-rays or gamma-rays for thepurpose of sterilization by elimination, inactivation or reduction ofpathogens including viruses, bacteria, fungi, yeast or prions. Thepresent invention also relates to methods for making consumer, medicaland industrial products from such compositions, as well as sterilizingsuch consumer products by applying an incident radiation that will beconverted to UVC radiation or electromagnetic radiation of shorterwavelengths.

It is known that UV-C light is “germicidal” because it can deactivatethe DNA of bacteria, viruses and other pathogens and thus destroys theirability to multiply and cause disease. In addition to such ultravioletgermicidal radiation, gamma rays and x-rays have been used to disinfectand purify water, air, and surfaces without the need for heat orchemicals. The short wavelength associated with UVC energy, specificallybetween about 250 to about 260 nm, and lower, provides the highestgermicidal effectiveness, and thus is lethal to a variety ormicroorganisms, including the most common molds, virus, and bacteria,such as salmonella, staphylococcus, streptococcus, legionella, bacillus,dysentery, infectious hepatitis, influenza, and rotavirus.

The most common way to use UVC technology has long been germicidal lampsthat emit a wavelength of energy of approximately 254 nm, since this isthe region of maximum germicidal effectiveness. While UVC technology isboth effective and free of unwanted by-products, it also has someinherent drawbacks, including the costs of the lamps and the dangersassociated with direct or reflected germicidal radiation.

Accordingly, there is a need for a more economical and safer method ofusing the powerful germicidal effects of UV technology. To that end, theInventor has investigated the use of organic or inorganic phosphors in acomposition that will benefit from germicidal effects.

A phosphor is a substance that exhibits the phenomenon ofphosphorescence, or a sustained glowing after exposure to light orenergized particles such as electrons. Phosphors have a finite emissiontime, with persistence being inversely proportional to wavelength.Because the persistence of the phosphor increases as the wavelengthdecreases, it is known that red and orange phosphors do not havesufficiently long glow times.

The organic and inorganic phosphors used in the present invention differfrom these traditional phosphors in that they have an indefinite glowtime. In addition, they have the ability to transfer electromagneticenergy of one frequency to a higher frequency (referred to as“up-converting”) or to a lower frequency (referred to as“down-converting”), depending on the rare earth metal used. Adescription of such phosphors is provided U.S. Pat. No. 5,698,397, whichis herein incorporated by reference. This patent describes the use ofsuch phosphors for biological and other assays.

Up-converting crystals, which take light or electromagnetic radiation ofone frequency and convert it to light of a higher frequency (thusshorter wavelength), appear to contradict a basic law of physicsdirected to conservation of energy. However, two, four or more photonsof a lower frequency or longer wavelength are converted into a singlephoton of higher frequency or shorter wavelength. Thus a number ofphotons of lower energy combine to produce one photon of higher energy.These compounds can emit visible light when irradiated with infra-redlight.

In contrast, down-converting crystals take light or electromagneticradiation of one frequency and convert it to light of a lower frequency(thus longer wavelength). These compounds can emit red or IR light whenirradiated with UV or visible light.

The Inventor has surprisingly discovered that when incorporated intovarious media, such as resins, ceramics, and fabrics, the disclosedphosphors can change the frequency of visible or infrared light togermicidal UVC radiation, or electromagnetic radiation of shorterwavelengths, such as x-rays or gamma-rays for the purpose ofsterilization by elimination, inactivation or reduction of pathogensincluding viruses, bacteria, fungi, yeast or prions. In addition,because the incident radiation is in the visible, infrared or longerwavelength ultraviolet region, there are no dangers associated withdirect or reflected UV radiation. Rather, all the germicidal UV andshorter wavelength radiation impinges only on the article or area thatcontains the inventive composition.

SUMMARY OF INVENTION

Thus, the present disclosure is directed to a composition for convertingelectromagnetic energy to ultraviolet C (UVC) radiation orelectromagnetic radiation of shorter wavelengths, such as x-rays orgamma-rays, for the purpose of sterilization by elimination,inactivation or reduction of pathogens including viruses, bacteria,fungi, yeast or prions. In one embodiment, the composition comprises, inan organic or inorganic media, at least one phosphor capable ofconverting an initial electromagnetic energy (A) to UVC radiation orelectromagnetic radiation of shorter wavelengths than UVC such as x-raysor gamma-rays. The materials that can be used herein is based on theternary rare earth metal orthophosphate, a crystalline solid composed ofa host lattice of yttrium lutetium scandium orthophosphate that isactivated with a small amount of dopants selected from bismuth,praseodymium and neodymium

There is also disclosed a method of sterilizing an article by exposingit to UV-C radiation or electromagnetic radiation of shorter wavelengthssuch as x-rays or gamma-rays. In one embodiment, the method comprisesexposing to visible, infrared or long wavelength UV radiation, acomposition comprising, in an organic or inorganic media, at least onephosphor capable of converting the visible or infrared light to UVCradiation or radiation of a shorter wavelength, wherein the article isexposed for a time sufficient to deactivate or kill at least onemicroorganism chosen from bacteria, virus, mold, protozoa, and yeast.

There is also disclosed a method of inhibiting abnormal cell growth in aliving body. In one embodiment, the method comprises exposing an articlecoated with the inventive composition, such as a stent, to visible or IRradiation (initial radiation A), so that it is converted to UVCradiation or electromagnetic radiation of shorter wavelengths such asx-rays or gamma-rays. The coated article can be exposed to the initialradiation (A) for a time sufficient to inhibit abnormal cell growthwithin the body, when the composition is in or on an implantable medicaldevice.

There is also disclosed a method of coating an article with asterilizing composition described herein. In this embodiment, the methodcomprises spraying, dipping, painting, or otherwise impregnating, on thearticle, a composition as described herein.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Certain terms used herein are defined below:

“Up-converting” refers to the ability to convert electromagnetic energyto a higher energy or shorter wavelength.

“Down-converting” refers to the ability to convert electromagneticenergy to a lower energy or longer wavelength.

“At least one” as used herein means one or more and thus includesindividual components as well as mixtures/combinations.

A “film,” as used herein, refers to a continuous coating, i.e., acoating without holes visible to the naked eye, which covers at least aportion of the substrate to which the composition was applied. Further,a film, as used herein, may have any thickness and is not restricted toa thin coating.

“Film-forming polymer” as used herein means a polymer which, by itselfor in the presence of a film-forming auxiliary, is capable, afterdissolution in at least one solvent, of forming a film on the substrateto which it is applied once the at least one solvent evaporates.

“Polymers” as defined herein comprise copolymers (including terpolymers)and homopolymers, including but not limited to, for example, blockpolymers, cross linked polymers, and graft polymers.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed. Reference will nowbe made in detail to exemplary embodiments of the present invention.

Phosphors are usually made from a suitable host material, to which anactivator is added. Suitable activators that may be used in the presentinvention include ytterbium, erbium, thulium, holmium, and combinationsof these materials. Non-limiting examples of activator couples includeytterbium/erbium, ytterbium/thulium, and ytterbium/holmium.

Generally, host materials comprise oxides, halides, sulfides, andselenides of various rare earth metals. Suitable phosphor host materialsthat may be used in one embodiment of the present invention includegadolinium, yttrium, lanthanum, and combinations of these materials.Particular non-limiting embodiments of such crystal matrices which maycomprise the host material include oxy-sulfides, oxy-fluorides,oxy-chlorides, or vanadates of various rare earth metals.

Non-limiting embodiments of the organic and/or inorganic phosphors thatcan be used as host materials in the present disclosure include sodiumyttrium fluoride (NaYF₄), lanthanum fluoride (LaF₃), lanthanumoxysulfide (La₂O₂S), yttrium oxysulfide (Y₂O₂S), yttrium fluoride (YF₃),yttrium gallate, yttrium aluminum garnet (YAG), gadolinium fluoride(GdF₃), barium yttrium fluoride (BaYF₅, BaY₂F₈), gadolinium oxysulfide(Gd₂O₂S), calcium tungstate (CaWO₄), yttrium oxide:terbium (Yt₂O₃Tb),gadolinium oxysulphide: europium (Gd₂O₂S:Eu); lanthanam oxysulphide:europium (La₂O₂S:Eu); and gadolinium oxysulphide: promethium, cerium,fluorine (Gd₂O₂S:Pr,Ce,F); and generally (YLuScA)PO₄, wherein A is anactivator selected from the group of bismuth, praseodymium andneodymium.

Other phosphors which may be used in the present composition, along withtheir characteristic absorption colors (and wavelengths) include, arenot limited to: Gd₂O₂S:Tb (P43), green (peak at 545 nm); Gd₂O₂S:Eu, red(627 nm); Gd₂O₂S:Pr, green (513 nm); Gd₂O₂S:Pr,Ce,F, green (513 nm);Y₂O₂S:Tb (P45), white (545 nm); Y₂O₂S:Tb red (627 nm); Y₂O₂S:Tb, white(513 nm); Zn(0.5)Cd(0.4)S:Ag green (560 nm); Zn(0.4)Cd(0.6)S:Ag (HSr),red (630 nm); CdWO₄, blue (475 nm); CaWO₄, blue (410 nm); MgWO₄, white(500 nm); Y₂SiO₅:Ce (P47), blue (400 nm); YAIO₃:Ce (YAP), blue (370 nm);Y₃Al₅O₁₂:Ce (YAG), green (550 nm); Y₃(Al,Ga)₅O₁₂:Ce (YGG), green (530nm); CdS:In, green (525 nm); ZnO:Ga, blue (390 nm); ZnO:Zn (P15), blue(495 nm); (Zn,Cd)S:Cu,Al (P22G), green (565 nm); ZnS:Cu,Al,Au (P22G),green (540 nm); ZnCdS:Ag,Cu (P20), green (530 nm); ZnS:Ag (P11), blue(455 nm); Zn₂SiO₄:Mn (P1), green (530 nm); ZnS:Cu (GS), green (520 nm);and the following crystals that emit in a UV-C range, e.g., from 200 to280 nm, such as from 225 to 275 nm: YPO₄:Nd; LaPO₄:Pr; (Ca,Mg)SO₄:Pb;YBO₃:Pr; Y₂SiO₅:Pr; Y₂Si₂O₇:Pr; SrLi₂SiO₄:Pr,Na; and CaLi₂SiO₄:Pr.

In one embodiment, the organic and/or inorganic phosphors are present inthe disclosed composition in an amount effective to convertelectromagnetic radiation of a frequency (A) to a higher frequency (B).While in theory, the up-converting crystals of this embodiment canconvert any electromagnetic energy to a higher energy (or shorterwavelength), in one embodiment, the electromagnetic radiation offrequency (A) comprises infrared or visible light, and the frequency (B)comprises ultraviolet (UV) radiation chosen from UVA, UVB, and UVC.

The organic and/or inorganic phosphors may be present in the disclosedcomposition in an amount ranging from 0.01% to 60% by weight, relativeto the total weight of the composition, such as from 0.1% to 30% or even1% to 15% by weight, relative to the total weight of the composition.

In one embodiment, the disclosed composition may further comprise anactivator for the organic and/or inorganic phosphors, such as aytterbium containing activator. Non-limiting examples of the ytterbiumcontaining activator include ytterbium/erbium, ytterbium/thulium,ytterbium/terbium, and ytterbium/holmium.

The organic and/or inorganic phosphors according to the presentdisclosure typically have an average particle size ranging from 1 nm to1 cm, such as from 1 nm to 1 mm, from 2 nm to 1000 nm, from 5-100 nm, oreven 10-50 nm. The concentration of the organic and/or inorganicphosphors in the inventive composition as well as in the above-definedregions and the size of the organic and/or inorganic phosphors can bemeasured by methods known for such which are well known in the art. Forexample, x-ray diffraction (XRD), scanning electron microscopy (SEM),transmission electron microscopy (TEM), and/or BET surface area analysismay be used.

The organic and/or inorganic phosphors according to the presentdisclosure are typically synthesized from rare-earth dopedphosphorescent oxide particles having the previously described sizes.The method further provides for homogeneous ion distribution throughhigh temperature atomic diffusion.

A solid-phase precursor composition (hereinafter referred to as “theprecursor composition”) is prepared by mixing one or more rare earthelement dopant precursor powders with one or more oxide-forming hostmetal powders. Stoichiometric amounts of host metal and rare earthelement are employed to provide rare earth element doping concentrationsin the final particle of at least 0.5 mol % up to the quenching limitconcentration.

In one embodiment, the quenching limit concentration is about 15-18 mol% for europium-doped Y₂O₃ nanoparticles, while it is about 10 mol % forerbium-doped Y₂O₃ nanoparticles. Also, for Yb and Er-codoped Y₂O₃nanoparticles, the quenching limit depends upon the ratio of Yb:Er.

The rare earth element dopant precursor powders include, but are notlimited to organometallic rare earth complexes having the structure:RE(X)₃

wherein X is a trifunctional ligand and RE is a rare earth element. Anyrare earth element or combinations thereof can be used (i.e., europium,cerium, terbium, dysprosium, holmium, erbium, thulium, ytterbium,lutetium) with particular mention being made to europium, cerium,terbium, holmium, erbium, thulium and ytterbium, as well as thefollowing combinations: ytterbium and erbium, ytterbium and holmium andytterbium and thulium.

Strontium can also be used, and for purposes of the present invention,rare earth elements are defined as including strontium. are earthelement dopant precursor powders include Yb(TMHD)₃, Er(TMHD)₃,Ho(TMHD)₃, Tm(TMHD)₃, erbium isopropoxide (C₉H₂₁O₃Er), ytterbiumisopropoxide (C₉H₂₁O₃Yb), and holmium isopropoxide (C₉H₂₁O₃Ho).

Examples of trifunctional ligands include tetramethylheptanedionate(TMHD), isopropoxide (IP), and the like.

The oxide forming host metal can be, but is not limited to, lanthanum,yttrium, lead, zinc, cadmium, and any of the Group II metals such as,beryllium, magnesium, calcium, strontium, barium, aluminum, radium andany mixtures thereof or a metalloid selected from silicon, germanium andII-IV semi-conductor compounds. Oxide-forming host metal powders includeY(TMHD)₃, Al(TMHD)₃, Zr(TMHD)₃, Y(IP), and Ti(IP).

The rare earth element dopant precursor powder and oxide-forming hostmetal powders are mixed to form the precursor composition, andvaporized. An inert carrier gas, such as, but not limited to, nitrogen,argon, helium, and mixtures thereof, transports the vaporized precursorcomposition to a low pressure combustion chamber that houses a flame.

The flame produces active atomic oxygen via chain-initiation reaction ofH+O₂=OH+O  (i)

A high concentration of oxygen in the flame activates and acceleratesthe oxidation of rare-earth ions and host materials through a series ofreactions:R+O→RO;  (ii)RO+O→ORO; and  (iii)ORO+RO→R₂O₃  (iv)

Reactions (ii) through (iv) are much faster than the oxidation reactionin low temperature processing represented by the reaction below;2R+3/2O₂=R₂O₃  (v)

The reaction represented by formula (v) has a much higher energy barrierthan the reactions in formulae (i)-(iv) in which radicals formed inflames diffuse and help produce faster ion incorporation.

Generally, in flame spray pyrolysis a higher flame temperature increasesparticle sintering and agglomeration. However, in one embodiment of thepresent invention, spherical, discrete particles are formed. It isproposed that in addition to residence time, the initial size of thevapor-phase particles in the vaporized precursor composition and theprecursor itself are the dominant factors that determine final particlesize. As the vaporized precursor composition passes through the flame,it directly reacts and releases heat to the flame increasing flametemperature. Thus, a shorter flame residence time is needed, whichallows for the production of smaller particles.

Temperatures ranging from about 1800 to about 2900° C. are used in oneembodiment, with temperatures ranging from about 2200 to about 2400° C.being particularly noted. Temperatures within this range producemonodispersed rare earth doped activated oxide nanoparticles withoutsignificant agglomeration having an essentially uniform distribution ofrare earth ions within the particles. Actual residence time will dependupon reactor configuration and volume, as well as the volume per unittime of vaporized precursor composition delivered at a given flametemperature. Cubic phase particles are obtained having an averageparticle size ranging from 5 to 50 nanometers, such as from 10 to 20nanometers. Until recently, it was not possible to obtain activatedcubic phase particles on a nanoscale. The particles also exhibitquenching limit concentrations heretofore unobtained.

The flame temperature can be manipulated by adjusting the flow rates ofthe gas(es). For example, the temperature of the flame can be increasedby increasing the methane flow rate in a methane/oxygen gas mixture.Guided by the present specification, one of ordinary skill in the artwill understand without undue experimentation how to adjust therespective flow rates of reactive gas(es) and inert carrier gas toachieve the flame temperature producing the residence time required toobtain an activated particle with a predetermined particle size.

Any reactive gas can be used singularly or in combination to generatethe flame for reacting with the vaporized precursor composition, suchas, but not limited to, hydrogen, methane, ethane, propane, ethylene,acetylene, propylene, butylenes, n-butane, iso-butane, n-butene,iso-butene, n-pentane, iso-pentane, propene, carbon monoxide, otherhydrocarbon fuels, hydrogen sulfide, sulfur dioxide, ammonia, and thelike, and mixtures thereof.

A hydrogen flame can produce high purity nano-phosphors withouthydrocarbon and other material contamination. In the depictedembodiments, the flame length determines particle residence time withinthe flame. Higher temperatures produce satisfactory nanoparticles withshorter flames. Flame length is similarly manipulated by varying gasflow rates, which is also well understood by the ordinarily skilledartisan. Increasing the flame length increases the residence time of theparticles in the flame allowing more time for the particles to grow. Theparticle residence time can be controlled by varying the different flowrates of the gases, and is readily understood by one of ordinary skillin the art guided by the present specification.

The compositions according to the invention further comprises at leastone organic or inorganic media in or on which the disclosed phosphorsare dispersed. In one embodiment, the organic media comprises a plasticresin, such as thermoplastic elastomers, high temperature plastics, andengineering thermoplastics. Non-limiting examples of such resins includea polymer or co-polymer of polyvinyl chloride (PVC), acrylonitrilebutadiene styrene (ABS), olefin, polycarbonate, styrene, nylon, andacetal.

It is possible to obtain an intimate mixture of the described phosphorsand resins by mixture them in a dry state and subsequently compoundingthem, which may be followed by forming them into desired shapes usingknown plastic forming techniques, such as injection molding.

The resins described herein are well-know to be formed into a variety ofplastic consumer and household goods, including hair combs, toothbrushes(and bristles), toilet seats, as well as in all types of food packaging.

Food packaging made from the inventive composition makes it possible toreduce the occurrence of common food bacteria, such E. coli andsalmonella, simply by exposing it to light, even while sitting on astore shelf. Thus, it may be possible to extend the life of a product byusing packaging made from the disclosed composition.

In another embodiment, the media is inorganic and comprises a ceramic,metal or fabric. For example, the inorganic media may be ceramic andcomprise glass or porcelain when the end-use is for a kitchen orbathroom fixture. Use of such compositions make it possible to formeating and cooking utensils that are resistant to common food bacteria,such E. coli and salmonella.

In one embodiment, the disclosed composition is used in a medicaldevice. Non-limiting examples of such medical devices include intralumendevices, such as stents, guidewires, and embolic filters. Commonmaterials that can be used in such intralumen devices include metalschosen from stainless steel or an alloy of nickel and titanium, commonlyreferred to as “NiTinols.”

When coated on such devices, it would be possible to achieve localizedUVC treatment even when such a device is inserted in the body. Forexample, by exposing the body to infrared (IR) radiation, which passesthrough the body, the IR radiation will convert to UVC radiation orradiation of a shorter wavelength such as x-rays or gamma rays when itcomes into contact with coated devices. This localized treatment willinhibit abnormal cell growth within the body, commonly referred to as“restenosis”, which remains a major limitation of percutaneous coronaryintervention (PCI).

Other non-limiting examples of medical devices that may benefit frombeing coated with the inventive composition include needles, catheters,such as intravenous catheters and urinary catheters, surgicalinstruments, material to be implanted into the body to repair or replaceblood vessels, or to be implanted as mesh as in hernia repair, such aspolytetrafluoroethylene or other fluoropolymer based materials,including those sold under the name Gortex®, valves for the heart orblood vessels, orthopedic devices such as prosthetic joints, ligaments,cartilage and the like, as well as neurosurgical implants, nervestimulators, deep brain stimulators, and the like.

Another embodiment is directed to containers for collection and/orstorage of bodily fluids, such as blood and blood components. Theplastic composition used in such containers typically includes a plasticresin that is suitable for contact with blood, such as polyvinylchloride, polyolefin or polyester. Such containers must be ablesterilize the container, which is typically carried out at hightemperatures.

It is possible, however, that exposure of such plastic compositions tohigh temperatures during steam sterilization, may cause degradation ofthe plastic composition. Degradation presents obvious problems,including a weakening of the overall mechanical strength of thecontainer. To avoid this problem, it is possible to form a flexiblesterilizable storage container for blood and blood components.

The plastic composition used in such containers typically includes aplastic resin that is suitable for contact with blood, such as polyvinylchloride, polyolefin or polyester, that is compounded with the phosphorsdisclosed herein. In addition to sterilizing the blood storage vesselfrom the disclosed composition, the blood stored in the vessel andunwanted contaminants located therein, such as hepatitis, can be easilyexposed to a lethal dose of radiation. Thus, in one embodiment, there isdisclosed a method of treating blood products by exposing blood productsthat are contained in a vessel made of the composition disclosed herein,to an initial radiation, which when intersected with the disclosedcomposition, is converted to UVC radiation or electromagnetic radiationof shorter wavelengths, such as x-rays or gamma-rays.

There is also disclosed an cover, such as a glass or plastic piece, forcovering an article to be disinfected. For example, in one embodiment,there is disclosed a plastic piece for covering the head of a toothbrushor the diaphragm of a stethoscope. In this embodiment, the plastic coveris capable of emitting the longer wavelength radiation to activate thecrystals and creating UV-C within the environment where the article isbeing disinfected. In one embodiment, the cover further comprisescoating on at least one of the interior or exterior walls that blocksthe UV-C from exiting the plastic cover, thus preventing UVC fromreaching those in the environment outside of the article that is beingdisinfected. In one embodiment, the coating for containing the UVCcomprises a thin metal layer, or an oxide that is transparent ortranslucent to the initial energy A but that prevent UVC from exitingthe cover, such as MgO, TiO₂, SiO₂ and Al₂O₃.

In one embodiment, the cover may be used on top of any product describedherein, such as a consumer product or medical device chosen from atoothbrush, comb, razor, stethoscope, or dental implant.

In another embodiment, the organic or inorganic media comprises a fabricderived from natural or synthetic fibers or blends of such fibers.Non-limiting examples of the natural fibers comprise cotton, wool, silk,and combinations thereof. Non-limiting examples of the synthetic fibersare chosen from polyesters, polyamides, acrylics, olefins, aramids, suchas Kevlar®, polyurethanes, polyethers, such as glycolpolyethyleneglycols, Spandex®, vinyl polymers and copolymers, and combinationsthereof. The polyesters comprise polyethyleneterephthalate andpolypropyleneterephthalate, and the polyamides comprise nylon.

The foregoing natural and synthetic fibers and fabrics made from suchfabrics, or combinations of such fabrics, can be impregnated or coatedwith the inventive compositions, and then formed into a bandage orarticle for wound treatment. Such a bandage would mitigate thepossibility of infection by exposing the wound to germicidal UVtreatment.

In another embodiment, the inventive composition may be dispersed on aliquid medium to form a sprayable slurry. This embodiment isparticularly suited to retro-fit existing articles to make themgermicidal. For example, it is possible to coat an existing article,such as a kitchen counter, by spraying, dipping, or painting onto thearticle, a composition described herein.

In this embodiment, the organic or inorganic media comprises a liquidfor forming a sprayable slurry comprising: (a) at least onepolyurethane; (b) at least one acrylic polymer or copolymer; and (c) atleast one mineral or organic fillers, the composition optionallycontaining at least one crosslinking agent. In one embodiment, at leastone of (a) to (c) is contained in an aqueous medium.

It is envisioned that consumer products made from or coated with theinventive composition can undergo almost continuous germicidal treatmentjust by nature of it being exposed to visible light, whether ambient orfor artificial. In addition to the foregoing, other advantageousend-uses include, but are not limited to, any article that comes intocontact with the general public, including door nobs, handrails,telephones, school desks, seat and arm cushions and headrests on publictransportation vehicles.

Other areas that would benefit from the use of articles made from theinvention include hospitals and doctor offices. For example, furniture,toys and other articles that have an increased exposure to virus,bacteria, yeast and fungi and can be almost continuously treated bysimply exposing them to light.

There is also disclosed a method of sterilizing an article by exposingit to UVC radiation or radiation of a shorter wavelength, the methodcomprising: exposing to long-wave ultraviolet, visible or infraredlight, a composition comprising, in an organic or inorganic media, atleast one phosphor capable of converting said visible or infrared lightto UVC radiation or radiation of a shorter wavelength, such as x-ray orgamma rays. In this embodiment, exposing is performed for a timesufficient to deactivate or kill at least one microorganism, includingthose chosen from bacteria, virus, mold, protozoa, and yeast.

In another embodiment, the method may be used to inhibit abnormal cellgrowth within the body. This is typically used when the composition isin or on an implantable medical device, such as a stent.

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, andso forth used in the specification and claims are to be understood asbeing modified in all instances by the term “about.” Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and in the attached claims are approximationsthat may vary depending upon the desired properties sought to beobtained by the present invention. At the very least, and not as anattempt to limit the application of the doctrine of equivalents to thescope of the claims, each numerical parameter should be construed inlight of the number of significant digits and ordinary roundingapproaches.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. The following examples are intended toillustrate the invention without limiting the scope as a result. Thepercentages are given on a weight basis.

What is claimed is:
 1. A composition for converting electromagneticenergy to UVC radiation or electromagnetic radiation of a shorterwavelength, said composition comprising: at least one phosphor capableof converting an initial electromagnetic energy (A) to a differentelectromagnetic energy (B), said different electromagnetic energy (B)comprising UVC, X-ray, or gamma radiation; and an organic or inorganicmedia containing said phosphor, wherein said organic media comprises aplastic resin, and said inorganic media comprises a ceramic, metal orfabric.
 2. The composition of claim 1, wherein the initialelectromagnetic radiation of frequency (A) comprises infrared radiationor visible light.
 3. The composition of claim 1, wherein said at leastone phosphor has an average particle size ranging from 1 nm to 1 cm. 4.The composition of claim 1, wherein said at least one phosphor ispresent in an amount ranging from 0.01% to 60% by weight, relative tothe total weight of the composition.
 5. The composition of claim 1,wherein said plastic resin comprises a polymer or co-polymer ofpolyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), olefin,polycarbonate, styrene, nylon, and acetal.
 6. The composition of claim1, wherein said ceramic comprises glass or porcelain.
 7. The compositionof claim 1, wherein said organic or inorganic media comprises a liquidfor forming a sprayable slurry of said composition.
 8. An articlecomprising the composition of claim 1, said article comprising aconsumer product, a children's toy, an animal toy, a medical device, areceptacle for biological fluids, a receptacle for holding drinkingwater, a bathroom fixture, a kitchen fixture, eating or cookingutensils, a cleaning product, or an article of clothing.
 9. An articlecomprising the composition of claim 1, said article comprising a coverfor a medical device or consumer product that: is transparent ortranslucent to said initial electromagnetic energy A and converts saidinitial energy to UVC radiation or radiation of a shorter wavelength.10. The article of claim 9, wherein said cover further comprises acoating on at least one surface that is transparent or translucent tothe initial energy but that prevents UVC from exiting the cover.
 11. Thearticle of claim 10, wherein said at least one coating comprises a metalor oxide chosen from MgO, TiO₂, SiO₂ and Al₂O₃.
 12. The article of claim9, wherein said consumer product and medical device is chosen from atoothbrush, comb, razor, stethoscope, and dental implant.